LPC MicrocontrollersのトピックRe: Input clamp current

Input clamp current

publius — Mon, 22 Jan 2018 12:06:05 GMT

Hi,

What's the maximum input voltage level on an un-powered device?

What's the maximum input clamp current of an IO?

I personally find the documentation on the input structure of LPC GPIO pins quite unclear.

Most pins are 5V tolerant, but only with Vdd present. But I can't seem to find the voltage levels when vdd is not present (LPC1317), see snapshot from the datasheet below:

In another thread it is mentioned that the input structure is a normal input clamp but that can't be the case due to the 5V tolerant pins.

Also, the input clamp current is not specified both for analog and digital pins.

If I follow the datasheet strictly this means that no signal can be connected to the micro-controller that isn't preceded by something that's on the same supply as the controller.

For example, the 3V3 rail of the controller could be short circuited or starting up while a 5V rail remains 5V.

Thanks in advance.

Re: Input clamp current

publius — Wed, 24 Jan 2018 09:12:16 GMT

Hi again,

Also, what are the specs for the open drain pins, PIO0_4 & PIO0_5 for the LPC1317?

Are these 5V tolerant and I2C compliant? With or without supply?

Could it be that the datasheet needs updating?

When I look in the datasheet of the LPC111x the open drain pins are mentioned but not for the LPC13xx:

Hopefully someone can help.

Some similar questions:

5V tolerant input

https://community.nxp.com/message/765563?commentID=765563#comment-765563

I2C 5V Toterant (with and without supply?)

https://community.nxp.com/message/750299?commentID=750299#comment-750299

Thanks

Re: Input clamp current

jeremyzhou — Fri, 26 Jan 2018 08:02:40 GMT

Hi,

Thank you for your interest in NXP Semiconductor products and 

the opportunity to serve you.

Unfortunately, the datasheet doesn't contain the kind of information you want and I will report your inquiry for the Doc team.

Thanks for understanding.

Have a great day,

TIC

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Re: Input clamp current

publius — Fri, 26 Jan 2018 09:26:31 GMT

Hi Jeremy,

Thanks for your response. Could you give an indication when to expect the data?

I'm currently designing a product with the LPC1317.

Thanks.

Re: Input clamp current

jeremyzhou — Mon, 29 Jan 2018 06:47:57 GMT

Hi,

Thanks for your reply.

Sorry, I'm not clear with the exactly schedule of releasing the updated datasheet.

And I will inform if I get it.

Have a great day,

TIC